SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b872d1f28b742d9e0d72fd4e8dba4880346fe9b2633addfb2149c53b85465896' 
  AND token = 'bVC/wIbmiD+dQxBk300rZBhdEF7G6VPr/HOOMZZVh8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}